Silencer



April 21, 1936. 5 QLDBERG 2,038,309

S ILENCER Filed July 25, 1954 5 Sheets-Sheet l ATTORNEY.

. INVENTOR.

S. OLDBERG April 21, 1936.

SILENCER ATTORNEY.

q v e o o o o a n 0 v o o u a 0 e n n u o I a 0 c 0 0 0 n 0 I u u I n a 0 a 0 0 n a a 0 April 21, 1936.

s. OLDBERG 2,038,309

SILENCER Filed July 25, 1934 3 Sheets-Sheet 3 noooo.n

nix-0.00.1101

vcucoI-oOa IN VENTOR.

ATTORNEY.

Patented 'Apr. 21, 1936 UNI-TED STATES PATENT OFFICE Claims.

This invention relates to silencers and more particularly to silencers used in connection with gases exhausted from internal combustion engines.

In the Oldberg Patent 1,950,455, dated March 13, 1934, there is disclosed a multiple pass silencer having an outer shell or casing containing several resonance units, including an inner through shell and an intermediate shell. Inasmuch as the construction of that patent requires two shells for each unit, a triple pass silencer of that construction requires seven shells in all. Therefore, that construction, while extremely efi'ective as a silencer, has proven to be somewhat more expensive than is considered desirable for certain classes or purchasers, and for this reason it is now proposed to provide a multiple pass silencer which is lighter in weight and less expensive in construction than the silencer of that patent, but which, despite its being provided with less parts than the silencer of that patent, is eflicient and satisfactory for the use to which it is put.

Detailed objects of the invention will be readily apparent to those skilled in the art upon reference to the following detailed description of embodiments of the same, reference being had to the appended drawings which show these embodiments.

In these drawings:

Figure 1 is an elevational section view of one form of silencer, as if on the line II of Figure 2;

Figure 2 is a transverse section as if on the line 2--2 of Figure l;

85 Figures 3 and 4 are similar views of a second embodiment; and

Figures 5a to 5d collectively show the shells and plates of the embodiment shown in Figures 3 and 4.

Figure 6 is a. transverse section view of a third embodiment.

Referring to Figures 1 and 2 of the drawings, it will be seen that the silencer there shown includes an imperforate outer shell or casing Ill and 45 a plurality of shells referenced I2, I4, and I6,

nested within one another and within the outer shell or casing III. The casing I0 is closed at its ends by inlet and outlet end headers I8 and I9.

The innermost shell I2 and the outer shell or 50 casing III are of cir ular cross section, whereas the intermediate shells I4 and. are of elliptical cross section, these being so dimensioned and arranged that the planes of their major axes coincide with each other and with a diametrical plane 66 of the outer shell. when the shells are assembled in the desired manner, as shown in Figure 2, the intermediate shells tangentially engage each other and the outer shell along lines referenced X, which lines represent lines of welding for mutually securing the intermediate shells and the outer shell in a rigid unitary assembly.

By virtue of this construction it will be readily observed that the innermost shell I2 is spaced from the intermediate shell I4 by a space 20' which varies in transverse dimension from a small dimension at the minor axis of the intermediate shell I 4 to a large dimension at the major axis of the intermediate shell I4. Intermediate shell I4 is spaced from intermediate shell I6 by two relatively isolated crescentshaped spaces 2I-22, and intermediate shell I6 is spaced from the outer shell III by two relatively isolated crescent-shaped spaces 23-24.

The innermost shell I2 is provided with a large area of minute perforations 26 which open into the space 20, and in the space 20 there are provided diaphragms 21 which divide the space 20 into a plurality of longitudinally separated sound absorption chambers.

One end of the innermost shell I2 passes through the inlet header I8 and is open at that end to provide an inlet for the silencer. The other end of the innermost shell I2 opens into an expansion chamber 28 within the intermediate shell I4, this chamber being closed by a plug 30 at a point longitudinally spaced from the end of the innermost shell I2.

The lower half only of the intermediate shell I4, at the expansion chamber 28 between the end of shell I2 and the plug 30, is provided with a large number of relatively large openings or throats 3|, whose aggregate cross section area is intentionally much larger than the cross-sectional area of the innermost shell I2. These throats communicate without substantial restriction the interior of the expansion chamber 28 with the space 2I between the shells I4 and I6. The lower half of the shell it, between the throats 3| and the inlet end of the shell I4, and the upperhalf thereof, between the inlet end of the shell I4 and the \plug 30, are provided with large areas of minute perforations 32, these communicating the relatively sealed spaces 2 I-22 with the relatively sealed absorption chambers 23-44, it being observed that the spaces 2 I-22 are sealed and isolated from each other, except at the expansion chamber 32a around the inlet end of the innermost shell I2 adjacent the inlet end of the intermediate shell II.

The upper half or the intermediate shell ll, be-

tween the plug 80 and the outlet end thereof which opens through the outlet end header II, is provided with a large number of relatively large openings or threats It which communicate the space II with the expansion chamber ll in the interior of the shell it beyond the plug II.

It will be observed that exhaust gases pass through the silencer in substantially the following path. Gases enter the silencer through the open inlet end of the innermost shell I! and course through that shell, discharging into the expansion chamber II; from there they flow with substantially no restriction through the throats 3| into thespace 2|,coursingthroughthatspaceto the expansion chamber Ila at the inlet end of the silencer; when they leave chamber 32a, they course through space 22 towards the outlet end of the silencer, from where they pass to expansion chamber 34 through throats II; from there, they leave the silencer.

During its flow in each course, the gases pass by the absorption chambers provided in and by spaces It, 23, and 24, and sound waves are absorbed in these absorption chambers.

The silencer here shown is economical of manufacture, and yet efiicient for silencing. The stampings which enter into the manufacture of the silencer can be made very easily and cheaply, and the assembly of the shells can be eifected at a minimum of cost.

Comparing the silencer here shown with the silencer shown in the patent above referred to, it will be observed that the silencer here shown utilises four shells to provide a triple pass construction wherein each turn is effected in an unrestricted expansion chamber, and wherein each course is at least partially surrounded by absorption chambers, whereas the construction shown in the patent above referred to requires seven shells to attain similar results.

It will also be observed that the elliptical shap The silencer of these figures includes an innermost shell 4| concentrically telescoped within an intermediate shell II, which in turn is eccentrically telescoped within a second intermediate shell 42. there being a plate 43 disposed between the shell II and the shell 42, the latter shell in turn being ecoentrically telescoped within an outer shell or casing N, there being a plate ll disposed between the shells 42 and I4.

Inlet and outlet end headers 41- close the ends of the silencer, with the innermost shell ll having its inlet end passing through a flanged opening of the inlet header to provide an inlet for the silencer and with the outlet end of the intermediate shell ll passed through a flanged opening of the outlet header ll and opening therethrough to provide an outlet for the silencer.

The annular space III between the innermost shell 40 and the intermediate shell II is provided with diaphragms II which form an absorption chamber therein. communication between-this chamber and the interior of the innermost shell 40 being eflected through a large number of minute perforations I2.

The end of the innermost shell 40 opposite the inlet end thereof pens into an expansion chamber ll within the intermediate shell ll, and this chamber is closed at a point remote from the aforementioned end of the innermost shell ll by a plug lie. The rear half only of the shell II, at the expansion chamber 83. is provided with a large number of relatively large openings or throats l4 and these communicate the interior of the expansion chamber, with substantially no restriction, with the space ll between the shell I and the shell 42, behind the plate 43. The plate 43, near its inlet end, is provided with a relatively large number of openings or throats II which communicate the space 55, near its inlet end, with the space l1 between the shells "-42, and in front of the plate 0, the throats It being large enough individually and in aggregate to present substantially no restriction to the flow of gases from space II to space 51.

The outlet endof the shell 4| on the front half thereof only, and between plug lie and the outlet header I8 is provided with a large number of relatively large openings or throats 58 which communicate the space 51, near the outlet end of the silencer, with the interior of shell ll beyond the plug 54, from where the gases leave the silencer.

It will be observed that gases entering the silencer through the open inlet end of the innermost shell ll course through that shell, passing the absorption space 50, and discharge into expansion chamber 53. From there the gases pass into space near the outlet end of the silencer and course back towards the inlet end of th silencer, passing absorption space 59 which communicates the coursing space I through a large area of minute perforations 80; the gases leave space it through throats It and enter space 51 near the inlet end of the silencer, coursing through that space past the absorption space H which communicates therewith through a large number of minute holes 82, until they reach throats ll in the shell ll; the gases then leave the silencer through these throats and the outlet end of shell ll The construction here shown, while it includes, in addition to the parts shown in the silencer of Figures 1-2, the two plates 48 and II, is nevertheless extremely economical of manufacture without being inefficient for silencing.

In Figure 6 there is shown a silencer of the type shown in Figure 4, but wherein the shells 40', ll,

42, and II are so arranged that the flat plates 43, 4!, which divide the shells 42, ll, longitudinally are adjacent, rather than diametrically opposed. This arrangement may be used if preferred, though it is substantially like that of Figure 4.

Now having described preferred embodiments of the invention, selected by way of example, reference will be had to the claims which follow for a determination of the scope of the invention.

What I claim is:

l. A triple pass silencer characterized by its having a shell and space arrangement including four relatively telescoped shells which will be hereinafter referred to as shells as, b, c, and d, of which shell a is within shell b, and is separated therefrom by spaced-b, shell I) is within shell 0, and is separated therefrom by space 11-0, and shell 0 is within shell 11, and is separated therefrom by space o-d, the interior of shell :1 providingthefirstgaspassfromtheinletendofthe silencer, sheH a being perforated so that its interior communicates with the space H so that the latter space may provide a silencer space for the first gas pass, one half of space bc providing the second gas pass, communication between the first and second gas passes being through shell b at a point beyond the end of shell a, the part of shell c adjacent the half of space bc that provides the second pass being perforated to communicate that half of space bc with the adjacent half of space cd so that the latter space may provide a silencer space for the second gas pass, the other half of space b--c providing the third gas pass, communication between the second and third gas passes being effected near the inlet end of the silencer, the part of shell adjacent the half of space bc that provides the third pass being perforated to communicate that half of space bc with the adjacent half of space cd so that the lattter space may provide a silencer space for the third gas pass.

2. A triple pass silencer characterized by its having a shell and space arrangement including four relatively telescoped shells which willbehereinafter referred to as shells a, b, c, and d, of which shell a is within shell I), and is separated therefrom by space aib, shell b is within shell 6, and is separated therefrom by space bc, and shell'c is within shell d, and is separated therefrom by space c-d, shell a terminating short of shell b,

shell b having a transverse closure between the ,And of shell a and its own end and having openings on opposite sides thereof and on opposite sides of the closure, shell a being perforated throughout its length, shell 0 being perforated throughout the length thereof between a point near the inlet end of the silencer and apoint near the closure of shell b, shells c and d being closed at their ends by end headers, space w-b being closed at its ends, shell a being open at its ends, and shell b being open at the end thereof remote from shell (1, a longitudinally extending plate in space bc dividing it into two 1ongitudinal halves and having apertures at the inlet end of the silencer communicating the halves.

3. A triple passsilencer characterized by its having a shell and-space arrangement including four relatively telescoped shells which will be hereinafter referred to as shells a, b, c, and d, of which shell ais within shell I), and is separated therefrom by space a-b, shell b is within shell 0, and is separated therefrom by space bc, and shell 0 is within shell d, and is separated therefrom by space cd, shell a terminating short of shell b, shell b having a transverse closure between the end of shell a and its own end and having openings on opposite sides thereof and on opposite sides of the closure, shella being perforated throughout its length, shell 0 being perforated throughout the length thereof between a point near the inlet end of the silencer and a point near the closure of shell I), shells c and d being closed at their ends by end headers, space a-b being closed at its ends, shell a being open at its ends, and shell b being open at the end thereof remote from shell a, a longitudinally extending plate in space bc dividing it into two longitudinal halves and having apertures at the inlet end of the silencer communicating the halves, and a longitudinally extending plate in space H dividing it into two longitudinally isolated halves.

4. A triple pass silencer characterized by its having a shell andspace arrangement including four relatively telescoped shells which will be hereinafter referred to as shells a, b, c, and d, shell a being utilized as the first pass, shell a being positioned within shellb so that the space therebetween forms a silencer chamber for the first pass, shell c being disposed about the combination of shells a and b to form a space between shells b and 0, means to divide the space between shells b and c into two longitudinally isolated passes communicating at their ends to form a continuous retroverted pass, means in the combination of shells a. and b, to connect the first pass with one end of the continuous pass, shell at being disposed about the combination of shells a, b, and 0, so that the space around shell c forms two silencer chambers for the two parts of the continuous pass, communication between shells a and b, and shells c and d being provided by perforations in shells at and c.

5. A triple pass silencer characterized by its having a shell and space arrangement including four relatively telescoped shells which will be hereinafter referred to as shells a, b, c, and d, the first pass being formed in shell a, shell b being disposed-about shell a so that the space therebetween provides a silencer chamber for the first pass, shell :1 opening into an expansion chamber formedin shell b, shell c being disposed about shell b to form a space therebetween, means in said space to divide the same into the second and third passes, these passes being in communication to form one continuous retroverted pass, one end of which opens to the atmosphere, communication means between the expansion chamber and the other end of the continuous pass, and shell d being disposed'about shell 0 so that the space around shell d forms two sllencer chambers for the two parts of the continuous pass, communication between shells a and b, and shells c and it being provided by perforations in shells as and c.

SIDNEY OLDBERG. 

